FLOUR MILLS. 
35 
some for sawing of wood, and others for stone. 
The improvements which have been made in 
the machinery of the flour mills in America 
are very great. The chief of these consist 
in a new application of the screw, and the 
introduction of what are called elevators, the 
idea of which was evidently borrowed from 
the chain pump. The screw is made by 
sticking small thin pieces of board, about 
three inches long and two wide, into a cy¬ 
linder, so as to form the spiral line. This screw 
is placed in a horizontal position, and by term¬ 
ing; on its axis it forces wheat or flour from 
one end of a trough to the other. For im- 
stance, in the trough which receives the meal 
immediately coming from the stones, a screw 
of this kind is placed, by which the meal is 
forced on, to the distance of six or eight feet 
perhaps, into a reservoir; from thence, with¬ 
out any manual labour, it is conveyed to the 
very top of the mill by the elevators, which 
consist of a number of small buckets of the 
size of tea-cups, attached to a long band that 
goes round a wheel at the top, and another 
at the bottom of the mill. As the band re-r 
volves round the wheels, these buckets dip 
into the reservoir of wheat or flour below, 
and take their loads up to the top, where 
they empty themselves as they turn round the 
upper wheel. The elevators are inclosed in 
P 8 
/ 
